The present invention relates to an improved design for camera film such as 35 mm film wherein the amount of usable exposure area of the film is vastly increased without increasing the overall size of the film. The present invention also relates to an improved circuit design to enable utilization of the improved film. The present invention incorporates an electronically controlled motor advance for film having light transmitting apertures along its edge that interact with a light source and a light sensitive switch for controlling the film advance motor.
The field of inventions in the area of cameras and film therefor is very crowded and there are many pieces of prior art in this general field. However, none of these pieces of prior art incorporate the novel features of the present invention. U.S. Pat. No. 2,539,499 issued to Walters is representative of the relevant prior art and discloses film utilizing apertured margins that coact with electrical switches for controlling motor operation of the film advance. This patent concerns perforated film which is transported with a motor drive system. There is no film advance circuit and no utilization of Light Emitting Diodes or Germanium Photo Diodes to advance and stop the advance of the film.
Novak U.S. Pat. Nos. 3,848,987, Fischer et al 3,481,261, Iwata et al 4,084,169, Stemme et al 4,196,993 and Hosono 4,075,644 all disclose other electric drive film advance arrangements utilizing film perforation responsive switches. More specifically, U.S. Pat. No. 3,848,987 issued to Novak discloses a cassette type sequence camera which operates similar to the principal of a movie camera wherein the film contains two sets of sprocket holes. U.S. Pat. No. 3,481,261 issued to Fischer et al on a film magazine and camera therefor discloses a mechanism wherein a pin is activated by a spring and the pin jumps in the perforation of the film and mechanically breaks the circuit. U.S. Pat. No. 4,084,169 issued to Iwata et al discloses an automatic film advancing system that contains a switching circuit which connects the motor to a power source in response to the closing of a shutter after photographing, and a detector circuit which produces a signal to cause said switching circuit to break off the feeding of the current when the current continues longer than a preset length of time. The system incorporates a claw hooked in the perforation of the film and this serves to turn the electronic switch off which breaks the circuit. U.S. Pat. No. 4,196,993 issued to Stemme et al also utilizes a mechanical claw apparatus to break the film advance circuit at a predetermined time. Finally, U.S. Pat. No. 4,075,644 issued to Hosono on a motor drive means for motor driven single lens reflex camera also uses a comparable mechanical claw apparatus which hooks the appropriate perforations in the film and breaks the film advance circuit. None of the above patents disclose the use of a light source and an LED device for controlling the motor circuit.
The following patents do disclose various electro-optical arrangements for sensing film apertures used in a motor controlled circuit for controlling the advance motion of film or other web materials: Nakatani et at U.S. Pat. Nos. 4,207,473, Endicott Jr. et al 4,160,169, Rube et al 4,140,915 and Nellis 3,809,910. More specifically, U.S. Pat. No. 4,207,473 issued to Nakatani concerns a frame detection circuitry for a microfilm reader apparatus. The side of the film has light reflection points, not holes or perforations. When light strikes these points, it reflects the light to a sensor which in turn provides a signal to an amplifier. The system is designed so that after a certain number of signals from reflection of the marks on the film are received by the sensors and transmitted, the film advance circuit is broken. U.S. Pat. No. 4,160,169 issued to Endicott Jr. et al for a parallel scanning system discloses the use of microimages on the film which light projecting on them from above. A light sensor is under the film. The system is capable of sensing when a given space of the film is not occupied by a microimage and this in turn is transmitted into a signal which serves to break the advance circuit. U.S. Pat. No. 4,140,915 issued to Rube et al discloses yet another apparatus and method for sensing the perforations in a perforated strip. This patent discloses a microfilm reader and counter. Light is projected on the film from two different angles. Under the film is a hole with a covered mirror. The mirror reflects the light back to an optical sensor. Depending on the light angle, the machine can detect which way the film is moving. Finally, U.S. Pat. No. 3,809,910 issued to Nellis concerns microfilm frame selection circuitry. First and second photodetectors are positioned within a bridge configuration and are optically coupled to a control track of a roll of microfilm having optically readable control indicia positioned therein. Each frame passes through a viewing gate. Appropriate circuitry and signals enable a predetermined frame of the roll of microfilm to be positioned within the film gate. Therefore, although the above four patents disclose electro-optical arrangements for sensing film apertures, none of them are related to cameras and none incorporate the unique circuitry of the present invention.
U.S. Pat. No. 4,240,733 issued to Ueda does disclose a light measuring and automatic exposure control circuit in FIG. 5 on page 3. However, this is for use with regular 35 mm perforated film. The system contains a motor drive and the film is stopped by normal mechanical means. The LED in this circuit is just for showing on the outside of the camera that the engine and the motor drive is in action and the LED is not used to advance the film or break the circuit to stop the film advance.
Finally, U.S. Pat. No. 2,536,156 issued to Brownscombe discloses the use of apertureless film. The patent relates to a motion picture camera and the film is advanced through a mechanical spring actuating advance system containing a big arm which swings back and forth.
Therefore, although there are many patents in the prior art which relate to the field of the present invention in general, none of them incorporate a unique system utilizing a Light Emitting Diode and Germanium Photo Diode which electronically control the advance of the film through pin holes on the edge of the film. None of the prior art systems incorporate the use of apertureless film with an electronic film advance in still cameras such as 35 mm cameras.